armacost



June 25, 1935. w. H. ARMACOST 19,619

ANTISLAGGING ARRANGEMENT Original Filed March 2, 1932 2 Sheets-Sheet l 1w 4 O I... 0 x w w mmz W W 0 0 0 M w E W 0 o Hi 0 0 00 j k 00 M M M o oo F. m z a o 0 M co 0 a x 36 dam A'ITORNEY June 25, 1935. w cos'r Re.19,619

ANTI SLAGGING ARRANGEMENT Original Filed March 2, 1932 2 Sheets-Sheet 2INVENTOR Wilbur H- Armw fli GI 7&1.

ATTORNEY Reissuea June 25, 1935 Re.

UNITED STATES PATENT OFFICE AN TISLAGGI'NG ARRANGEMENT Wilbur H...AImecDst, New York. N. Y., asslgnor to The Superheater Company, NewYork, N. Y.

Original No. 1,983,333, dated December 4, 1934, Serial No. 596,234,March 2, 1932. Application for reissue January 26, 1935, Serial No.3,629

9 Claims. (CI. 122--303) My invention relates to coal fired superheaterFurther objects and advantages of my invenbollers designed to operate athigh combustion tion will be apparent to those skilled in the art rates.from the following description taken with the With the adoption ofmechanical firing means accompanying drawings. for coal such as stokersand powdered fuel burn- The novel features of my invention are pointed 5ers, it was found that the high combustion rates out in the appendedclaims. In order that the permitted or made economically feasible bysuch invention may be easily and fully understood, means caused seriousslagging of the generating however, I will now describe in detail and incontubes nearest the furnace in the case of boilers of nection with theaccompanying drawings, a boiler the well known straight tube type. Ithas, thereand two forms of superheatcr units selected by 10 fore, becomethe practice in such boilers having way of example from a number ofpossible emmechanical coal firing means to arrange several bodiments ofmy ihveniiOn- I the a s, horizontal rows of generating tubes which lieFig. 1 is a sectional elevation of a mechanicalnearest the furnace toform an anti-slagging 1y fired superheater boiler having my invention isscreen or bank. In such so-callecl slag bank, pplied th ret the watertubes are placed farther apart thereby F g. 2 is a a a y e t on o ne ofwidening the passages for the gas-and ash between the tubes andpermitting the ash particlesto cool Fi 3 is a fragmentary section of o prti n f enough by radiation prior to contacting with a t up adapted for1153.111 my inVehtiOn.

water cooled surface to prevent their adhesion to ut hav g a differentform o u from a 20 such surface. The wide passages b t en th illustratedin Figs. 1 and 2 and taken on a line tubes further prevent bridgingbetween the tubes corresponding to only a p of the line even when acertain amount of sla ging oc ur Fig. 4 is a detail View in elevation ofa portion In the straight tube type of water tube boiler of e of theunits of the y showfl i g. 8.

2'5 furthermore, it has become customary to separate 5 is va bottom p wO t element a portion of the generating :tubes from another Shown in toprovide .a so-roalled interdeck space for the re- 6 is a 889mm n the e0f ceptlon of a superheater. Such an arrangement looking n the directionof the a owsof the superheater has been found advantageous 7 is a c o onthe e of Fi in many respects, but the present tendency is looking in thedirection of the arrows. 30 toward ever increasing final steamtemperatures, In the ordinary lnterdeck superheater boiler, and manyrecent installations and, others in con there is employed a steam andwater drum Ill contemplation, require a steam temperature difficultneoted y downcomers to ead s H from to obtain by an jntendecksuparheater a previwhich extend somewhat upwardly tubes I5, 16

ously constructed. It is possible to increase the f rm g n pp ing bankand c nnect- 35 supcrheat derived from a superheater in the ins at theirupper ends with de s '8 from ter deck position by another of the radianttype which steam and water are delivered to drum I]! but this involvesconsiderable additional expense. thm cificlfiators Q h h fi Moreover,the tubes of a superhcater are ordiand 8 nd spaced therefrom ar twoother group narily arranged much closertogetlser than are the 0f headers22 and fipe t y- Headers 22 0 generating tubes of a boiler so that thetendency are Connected headers 44 y d w oom nipto slag across thesuperheater tubes is greater ples 26 and headers 24 are connected toheaders than is the case with steam generating tubes at E8 by risernipples 28. It will be seen that the ancqual distance from the fire. athas therefore ppl a d 2B are sufficiently long to pro de 46 b enimpossible to increase the temperature of an interdeck space 35] tor asuperheater 3?. Ex- 46 steam delivered by an interdeck superheater bytending between head rs 22 and N are two moving it relatively closer tothe furnace because horizontal TOWS generating tubes 16', 46', set ofdifiiculties from slagging. the samedistances apart both-vertically andhori- It is the -.princlpal Object of my lmventi t zontelly as the tubes1 6. Below the tubes H? and 50 provide an .arrarmement whereby aninterdeck also extending between headers 22 and f is an 50 superheatermay the arranged to give steam of antislagging bank or screen 84. Belowscreen relatively high temperature in a mechanically 34 is the usualfurnace chamber 35 and aburner fired coal rimming superheater boilerwhile pre 35a for powdered coal is shown for feeding time] venting.di'flicultics from slagging of the superto such'chamber.

matur- Ordinarily, the-tubes in slag screens such as 55 all) are spacedhorizontally the same distance between centers as the tubes I6 and I6but are spaced vertically a somewhat greater distance than tubes l6 andHi. In order, however, that the gases striking the superheater 32 may behotter than has been the custom previously, 'and thereby to enable suchsuperheater to deliver steam at higher temperature, I have given thebank 34 a special arrangement which achieves the desired object butwhich involves a minimum of additional expense. In the arrangementillustrated every other tube in each horizontal row of bank 34 isomitted although the usual number of tubes in the vertical direction asnormally used in such banks is retained, namely, four. However, headers22 and 24 in the vertical zone covered by tubes 36 of bank 34 are soformed that the tubes 36 are arranged in groups of tour, so set that thecenters of the various groups forming bank 34 define parallel arcs, thetop and bottom tubes of each group being in a given vertical line andthe two intermediate tubes of each group also being on a given verticalline, but offset slightly from the line of the top and bottom tubesthereby providing relatively wide and unobstructed lanes for the passageof gas therethru. The spaces between adjacent rows of tubes 86 and 36are, of course, unimpeded as otherwise the desired rates of combustionin furnace could not be obtained. The gases therefore reach the tubes ofthe superheater 34 at a considerably higher temperature than in theordinary arrangement. As shown in Fig. 2 and as is ordinarily the case,the tubes of the elements 38 and 33 of superheater 34 are arranged muchcloser together than the generating tubes I6 and I6. Also, the metaltemperature of elements 38 and 38 is higher than that of tubes I6 sothat, unless special means were provided, diiliculty from slagging ofthe superheater tubes would occur when operating at the ordinarily highrates of combustion employed at present with mechanically fired coalburning boiler furnaces. In order to avoid such difliculty, I havearranged the elements 38 so that they begin lower down than thealternate elements 38 and therefore end at a lower level so that thelowermost row of tubes of the superheater 32 is more widely spaced thanis the case throughout the body of the superheater thereby providing azone of material vertical height in which the ash particles in the gaseshave a relatively low velocity and may lose sufficient heat to thesuperheater elements by radiation to prevent slagging of the tubes inthe zone of the superheater in which the tubes are closely spaced.

However, various arrangements may be used for obtaining relatively widespacing of the tubes of the superheater in a zone along the lower edgethereof and I have illustrated in Figs. 3 to '7 inclusive a form of unitdifferent from that appearing in Figs. 1 and 2, but equally well adaptedto achieve the desired result. As appears clearly from Figs. 1 and 2,the units 38 and 38' have their tubes of the same diameter. In thesuperheater 34a, illustrated in Fig. 3, however, the alternate units 39and 39' are not alike, units 39' having only tubes 40 of uniform size,while units 39 have upper portions composed of tubes 49 of larger sizethan the tubes 42 composing the lower portions of such units. As appearsmore clearly in Figs. 4, 5 and 6, the steam in units 39 flows in seriesthru the tubes 40 and 42, the lower ends of the tubes 40 of elements 39being bifurcated at points 44 so that each tube 40 of such an elementdelivers to a pair of tubes 42, 42, the upper portions 46, 46 of whichlie in a given horizontal plane. The parts 46 of the small diametertubes, however, are connected by return bends 48 and 50 with the lowerportions of the tubes 42 which lie one above the other in the samevertical plane as the tube portions 40 of the same element, bends 48 and59 lying in planes inclined toward each other, as appears in Fig. '7,and bend in being of greater diameter than bend 48 to permit the changein position of the small tubes of a given pair as just described. Theelements 39' which alternate with elements 39 do not have any smalltubes 42. As appears clearly from Figs. 3 and 6, the resultingarrangement of the tubes 40 and 42 is such as to provide relatively widespaces 52 between adjacent pairs of tubes 42 in the zone along thebottom of the superheater composed of elements 39 and 39. In Fig. 3,tube sections 46 are shown as quite close to the lower row of tubes 49.This is due to the fact that the lower rows of tubes 49 in elements 39'are at a lower level than the lower rows of tubes 40 in elements 39.However, I do not limit myself to this.

It will be understood further that I do not intend to limit myself inall cases to details of the foregoing description and that the appendedclaims are to be taken in their broad sense.

What I claim is:

1. A boiler having a bank of generating tubes inclined to thehorizontal, a plurality of rows of Water tubes between which the gasflow is unimpeded, forming a group having an anti-slagging eifect andspaced below said bank, and a superheater between said bank and saidsecond mentioned tubes and so arranged that all the gases passingbetween said rows pass also between the tubes of the superheater, saidsuperheater having those of its tubes adjacent its lower side arrangedto produce a substantial additional antislagging effect whereby saidsuperheater may receive higher temperature gases without slagging upthan would otherwise be the case.

2. A superheater boiler having a, bank of generating tubes inclined tothe horizontal, additional generating tubes below and spaced from saidbank but having the same distance between centers as the tubes in saidbank, water tubes below said additional tubes having approximately twicethe horizontal spacing between centers as the tubes of said bank toproduce an anti-slagging effect, and a superheater in the space betweensaid tube bank and the tubes immediately below it and so arranged thatall the gases passing between said rows pass also between the tubes ofthe superheater, said superheater having the 1 tubes in the zone alongits lower side arranged to produce a substantial anti-slagging effectadditional to that produced by said water tubes.

3. The combination as set forth in claim 2 and in which the last groupof tubes is arranged to form parallel arcuate lanes for the gases.

4. A boiler having a furnace and mechanical means for feeding coalthereto, a bank of generating tubes inclined to the horizontal andarranged to receive heating gases from said furnace, a plurality of rowsof water tubes intermediate said bank and said furnace and set fartherapart on the average than those of said bank to have an anti-slaggingeffect, and a superheater intermediate said bank and said secondmentioned tubes and so arranged that all the gases passing between saidrows pass also between the tubes of the superheater, said superheaterhaving those of its tubes adjacent its lower side arranged to produce asubstantial additional anti-slagging elfect whereby said superheater mayreceive higher temperature gases without slagging-up than wouldotherwise be the case.

5. A superheater element adapted for use in an anti-slagging superheaterand having a relatively large tube arranged to deliver to a pair ofrelatively small tubes, said smaller tubes having two sections lyingparallel in a given plane and two other sections lying parallel but in aplane substantially at right angles to that of said first mentioned pairof sections, and connections whereby said first mentioned sectionsdeliver to said second mentioned sections, said second mentioned pair ofsections lying substantially in the same plane with a larger tube of theelement.

6. The combination in a superheater boiler of a main bank of generatingtubes, a group of tubes spaced below said bank and set farther apart onthe average than the tubes of said bank to have an anti-slagging effect,and a superheater in the space between said bank and said groups andarranged to provide an additional anti-slagging efi'ect, saidsuperheater being so arranged that all the gases passing through saidgroup of tubes pass also between the tubes of the superheater.

'7. The combination in a superheater boiler of a group of generatingtubes arranged to have an anti-slagging effect, a superheater adjacentsaid tubes and arranged to have an additional antislagging effect, andadditional generating tubes above said superheater and set closertogether than those of said group.

8. The combination in a superheater boiler of a group of steamgenerating tubes arranged to have an antislagging effect, and asuperheater adjacent to said tubes and following them in the directionof gas flow and arranged to have an additional anti-slagging effect.

9. The combination in a superheater boiler of a group of steamgenerating tubes inclined somewhat from the horizontal and arranged tohave an anti-slagging effect, and a superheater comprising tubesadjacent and parallel to said steam generating tubes and following themin the direction of gas flow and arranged to have an additionalanti-slagging effect.

WILBUR H. ARMACOSTl

